The round baler has a baling chamber, and a pressing roller (30) wound with a pressing belt (32). The pressing roller is set abutting with the drivable rollers (34) and the revolving rollers by the lateral guides (66) in the axial direction. The lateral guides are arranged immediately before the drivable roller and at both sides of the pressing roller, corresponding to the baling operation force movement direction of the pressing roller. The rotating disks (68) having grooves (76) are provided in the lateral guides.